0.3 A C-curve MCB for panel protection
The 5SY4314-7: This means it trips at 5–10 times the rated current (1.5–3.0 A magnetic trip), making it suitable for protecting control transformers, relay coils, and signal circuits where inrush is moderate but short-circuit protection still needs to be fast.
DIN rail fit and temperature derating
The 0.3 A rating is at 35 °C ambient. Budget the derating at the design stage, not after commissioning.
